Microsoft now owns some of the biggest videogames in the world. What it does with them could ripple across the entire industry—for good and bad. 

The biggest of those games is in the spotlight this week, as Activision Blizzard’s latest “Call of Duty” sequel went on sale Friday. Called “Modern Warfare III,” the new game is notable for a couple reasons. The first is that much of its development took place during a period in which Activision’s future structure was uncertain, as the $75 billion acquisition by Microsoft took nearly two years to close. Intense opposition from regulators made the deal far from a sure thing; it closed last month almost immediately after U.K. regulators ended their extended probe following concessions from Microsoft.